With the continuous development of science and technology, various electronic devices are widely used in people's work and daily life, and bring great convenience to people's work and daily life.
For an analog integrated circuit, in a case that an input voltage varies in a wide range, it is required to convert the input voltage varying in the wide range into a low constant voltage using a power supply conversion module, to supply power to an internal circuit using the low constant voltage.
In a conventional power supply conversion method, a low dropout regulator (LDO) is integrated in a chip. In the LDO, an applied input voltage is decreased by an excessive voltage through a transistor operating in its linear region, to generate a regulated output voltage.
The LDO has an advantage of a high-precision output voltage. However, for the LDO, it is required to provide a reference voltage in a bandgap voltage reference and complicated feedback loop compensation is involved, thereby resulting in a highly complicated design and occupying a large chip area. For some analog integrated circuits, the requirement on the precision of a power supply voltage is not very high, it is only required that the power supply voltage is within a safe range such that an internal circuit is not burnt. In addition, the requirement on the power supply capability is also not very high, which is usually below a level of mA, the usage of LDO may result in an unnecessary additional cost.
Currently, there is not a simple and reliable technology for providing multiple output power supplies. For example, with the LDO, only one output power supply may be provided. If two output power supplies are demanded, it is required to arrange two LDOs, thereby occupying a larger chip area.